Regularly sleeping for more or less than seven hours per day is associated with an increased risk of cardiovascular disease, a new study suggests, Xinhua reported.
Researchers at West Virginia University School of Medicine based their finding on data from 30,397 adults who participated in the 2005 National Health Interview Survey, which collected information on demographic factors, socioeconomic characteristics, lifestyle and health.
Sleep duration was assessed by the question, "On average, how many hours of sleep do you get in a 24-hour period?"
Eight percent of the study population reported sleeping five hours per day or less, including naps. Multivariable logistic regression analysis revealed that their risk of any cardiovascular disease was more than two times higher than that of people who reported a daily sleep duration of seven hours. Nine percent of participants reported sleeping nine hours or more per day, and they also had an elevated risk of cardiovascular disease.
Results were adjusted for potential confounders such as age, sex, race, smoking, alcohol consumption, body mass index, physical activity, diabetes, hypertension and depression. Participants reported 2,146 cases of cardiovascular disease, which was defined as a physician diagnosis of angina, coronary heart disease, heart attack or stroke.
The study suggests that short and long sleep durations are independent risk factors for cardiovascular disease.
"Our study findings suggest that abnormal sleep duration adversely affects cardiovascular health," said principal investigator Anoop Shankar, MD, PhD, Associate Professor in the Department of Community Medicine at the school. "Sleep disturbances may be a risk factor for cardiovascular disease even among apparently healthy subjects."
The study was published in the Aug. 1 issue of the journal SLEEP.
Although individual sleep needs vary, the American Academy of Sleep Medicine recommends that most adults should get about seven to eight hours of nightly sleep to feel alert and well rested during the day.